Pressurized fluid feed system for fluid bearings of mobile pallets and the like

ABSTRACT

A fluid feed system for supplying pressurized fluid to the fluid bearings of mobile pallets and the like is disclosed which includes a fluid conducting probe means mounted on each pallet or the like and extending into an elongated pressurized chamber disposed along the path to be traveled by the pallets or the like. According to this invention the pressurized chamber includes resilient wall means preventing escape of pressurized fluid therefrom but adapted to receive the fluid conducting probe means of the pallets or the like and to accommodate relative movement of such probe means with respect thereto. A specific application of the system to mobile air pallets is described in which an elongated subsurface pressurized air chamber is disposed along the path to be followed by such pallets.

' United States Patent Maras et al.

14 1 Aug. 26, 1975 1 PRESSURIZED FLUID FEED SYSTEM FOR FLUID BEARINGS OF MOBILE PALLETS AND THE LIKE [75] Inventors: Frank Anthony Maras, Aurora;

Donald Franklin Durham, Peoria, both of I11.

[73] Assignee: Caterpillar Tractor Company,

Peoria, 111.

[22] Filed: May 24, 1974 [21] Appl. No.: 473,137

[52] US. Cl 180/116; 137/580 [51] Int. Cl. B60V 1/00 [58] Field of Search 180/116, 119; 104/23 FS; 214/1 BE; 137/580 [56] References Cited UNlTED STATES PATENTS 2,798,506 7/1957 Baker 137/580 3,012.574 12/1961 Baker.... 137/580 3,190,460 6/1965 Rubin 214/1 BE 3,217,725 11/1965 Varian 137/580 X 3,580,401 5/1971 Stahl 180/119 X Primary ExaminerDavid Schonberg Assistant ExaminerT. L. Siemens Attorney, Agent, or FirmPhillips, Moore, Weissenberger, Lempio & Strabala 57 ABSTRACT A fluid feed system for supplying pressurized fluid to the fluid bearings of mobile pallets and the like is disclosed which includes a fluid conducting probe means mounted on each pallet or the like and extending into an elongated pressurized chamber disposed along the path to be traveled by the pallets or the like. According to this invention the pressurized chamber includes resilient wall means preventing escape of pressurized fluid therefrom but adapted to receive the fluid conducting probe means of the pallets or the like and to accommodate relative movement of such probe means with respect thereto. A specific application of the system to mobile air pallets is described in which an elongated subsurface pressurized air chamber is disposed along the path to be followed by such pallets.

10 Claims, 4 Drawing Figures SWEET l U{ 2 PRESSURIZED FLUID FEED SYSTEM FOR FLUID BEARINGS OF MOBILE PALLETS AND THE LIKE BACKGROUND OF THE INVENTION This invention relates to mobile load moving devices such as pallets and the like utilizing fluid bearings to move loads on a thin film of flowing fluid and more particularly to a fluid feed system for supplying high pressure fluid to the fluid bearings of such pallets and the like.

Mobile vehicles utilizing a high volume, low pressure air cushion to support them above the ground or other surface for substantially frictionless movement in any direction are well known. Such ground effect vehi cles include an appropriate self-contained power means for generating the required high volume, low pressure air flow and are thus highly mobile but because of the size and weight of such power means the load capacity of a given size ground effect vehicle is severely limited.

More recently mobile load bearing devices such as pallets and the like utilizing high pressure, low volume fluid bearings for supporting loads above a surface for substantially frictionless movement on a flowing film of air have been developed. Because high pressure, low volume fluid flow can be efficiently conducted through extensive conduits to desired points of utilization, it is possible to supply the pressurized fluid to the pallets or the like from a remote source of pressurized fluid. Thus, the pallets or the like need not support anything except the desired load and it has been found that the load capacity of such a system is limited only by the highest fluid pressure and air flow for which the system is designed. The mobility of the pallets or the like is, of course, necessarily restricted by the location and nature of the conduits which supply the high pressure, low volume fluid flow thereto from the remote source of such fluid.

According to one system known in the prior art, the I high pressure, low volume fluid flow is supplied to the pallets or the like by means of an elongated conduit or conveyor having a plurality of restricted upwardly directed orifices distributed along the length thereof. The pallets or the like having a flat surface superimposed on such conduit or conveyor are supported thereabove by the continuous flow of high pressure fluid from such orifices and the orifice may be slightly inclined to impart a longitudinal motion to the pallets or the like along such conduit or conveyor.

However, it will be understood that the load carrying capacity of the pallets or the like is limited by the volume of fluid flow required to maintain the desired high pressure at all of the orifices of the conduit or conveyor. Thus, a very large power means would be required to provide a remote source of pressurized fluid capable of moving a substantial weight over a long distance using this system.

For this reason it is common practice in the prior art to supply the high pressure, low volume fluid flow to the pallets or the like by means of an elongated flexible conduit having its only outlet atthe pallet or the like which is equipped with appropriate fluid bearing structures to which the pressurized fluid is applied. However, such elongated flexible conduit presents a safety problem as well as being unsightly and subject to excessive wear in use. Such problems remain even where a vrigid conduit is used having a plurality of valved stations along its length for the attachment of shorter lengths of flexible conduit each adapted to supply the pallet for a given length of travel along the rigid conduit. In addition the repeated coupling and uncoupling of such shorter conduits as the pallet or the like is moved along the rigid conduit is time consuming and inefficient.

It is an object of this invention to provide a system for supplying high pressure, low volume fluid flow to a mobile pallet or the like from a remote source without re quiring the use of elongated flexible conduit.

It is a further object of this invention to provide a system for supplying high pressure fluid to a mobile pallet or the like from a remote source in which the volume of fluid flow in the system is reduced toward the minimum required to move the desired load.

It is yet another object of this invention to provide a system for supplying high pressure, low volume fluid flow to a mobile pallet or the like from a remote source in which such flow is continuous throughout the travel of the mobile pallet or the like in the system.

SUMMARY OF THE INVENTION Briefly, the system for supplying a continuous low volume flow of high pressure fluid to a mobile pallet or the like during movement thereof along a given path according to this invention comprises a fluid conducting probe projecting from the pallet or the like and an elongated sealed conduit connected to a source of pressurized fluid and extending along said given path, said conduit having wall means adapted to receive said probe therethrough and to accommodate relative movement of said probe with respect thereto while preventing the escape of pressurized fluid from said conduit other than through said fluid conducting probe. According to this invention, such wall means comprises a pair of elongated parallel planar surfaces extending along the axis of elongation of the conduit and compressively abutting each other with given force per unit square, at least one of such surfaces being flexible in directions transverse thereof and being provided on an elongated member of resilient material, the crosssectional dimensions of such elongated member and the given force of abutment being sufficient to cause such member to be substantially rigid with respect to the maximum fluid pressure in the conduit while retaining resilience perpendicular to the abutting surfaces.

BRIEF DESCRIPTION OF THE DRAWING The foregoing and other objects and features of this invention will be more fully understood from a reading of the following detailed description of a preferred embodiment thereof in conjunction with the attached drawing wherein:

FIG. 1 is an end view of a mobile pallet in accordance with the system of this invention used as an assembly platform for heavy earth moving equipment, which FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawing, the teaching of this invention is shown as applied to an assembly line for heavy earth moving equipment. FIG. 1 is a cross-sectional view of the assembly line taken in the direction of movement of the equipment along such line for assembly. The assembly line 10 comprises a relatively smooth, flat concrete assembly floor 11 along which the equipment 12 is moved by means of a mobile air pallet 13. In the particular embodiment of FIG. 1, the equipment 12 is a track mounted hydraulic excavator weighing several tons and shown in fragmentary end elevation. The air pallet 13 comprises a pair of substantially flat, laterally spaced, inter-connected platforms l4 and 15 each individually supporting one of the tracks 16 of the hydraulic excavator 12. The air pallet 13 is guided along the assembly line 10 by means of a rail 17 mounted on the assembly floor 11 and adapted to be engaged by a guide wheel 18 rotatably mounted on one side of the pallet 13. The air pallet 13 is slidably supported above the assembly floor 11 upon a thin film of air provided by a plurality of inflatable, annular air bearings 19 which are provided under each of the platforms 14 and 15 of the pallet 13.

While the air bearings 19 may be of any type commercially available, those manufactured by Rolair Systems, Inc. are particularly contemplated and the platform 14 of FIG. 1 is broken away to show such an air bearing in cross-section. Referring to such crosssection, it will be seen that the air bearings 19 comprise an annular inflatable bag 20 having one or more apertures 21 in its inner periphery. High pressure, low volume air flow introduced into such bag 20 by means of a pipe 22 carried by the pallet 13 inflates the bag 20 and flows out through the apertures 21 to provide the thin film of air which supports the pallet 13 for slidable movement along the assembly floor 11 of the assembly line 10.

According to the teaching of this invention, a novel air feed system shown generally at 30 in FIG. 1 is provided for supplying a high pressure, low volume supply of air from a source (not shown) to the pipes 22 of the pallet and thus to the air bearings 19. As best shown in FIG. 1, the novel air feed system includes an elongated conduit 31 mounted in the assembly floor 11 and extending along the assembly line 10 parallel with the guide rail 17. A probe member 32 mounted on the air pallet 13 projects therefrom into the conduit 31 providing communication between the conduit 31 and the pipes 22 of the air pallet 13.

Referring to FIG. 3, an enlarged cross-sectional view of the conduit 31 and probe 32 is shown. According to this embodiment of the invention the conduit 31 comprises an elongated channel member 33 of U-shape cross-section with flange members 34 and 35 extending outwardly from the free ends of the legs thereof.

According to the teaching of this invention the open side of the U-shaped channel member 33 is closed by conduit wall means adapted to receive the probe 32 therethrough into communication with the conduit 31 and to accommodate relative movement of such probe means with respect to the channel member 33 while preventing the escape of pressurized air from the conduit 31 other than through the probe 32. Thus, such conduit wall means comprises a pair of elongated parallel planar surfaces 42 and 43 extending along the axis of elongation of the conduit 31 and compressively abutting each other.

According to the embodiment of this invention shown in the drawing, each of such surfaces 42 and 43 may be provided by a different one of a pair of thin, elongated planar strips of material having a low coefficient of friction such as Teflon for example. Also, as shown in the drawing, each of such pair of Teflon strips may be mounted on a different one of a pair of elongated resilient members 44 and 45 made of elastomeric material or the like. The resilient members 44 and 45 may in turn each be mounted on a different one 34-35 of the flanges at the free ends of the legs of the channel members 33 by means of a pair of appropriate rigid support members 46 and 47 embedded therein and projecting from their respective outer sides.

According to the teachings of this invention, the elongated resilient members 44 and 45 are mounted on the flanges 34 and in such a way that the planar surfaces 42 and 43 carried thereby compressively abut each other with a given force per unit square. Such given force per unit square, as well as the crosssectional dimensions of the elongated resilient members 44 and are selected with respect to the maximum pressure of the air in the conduit 31 so that such resilient members 44 and 45 will be substantially rigid with respect to the pressure of the air within the conduit 31 and an air tight seal will be maintained between the surfaces 42 and 43. However, such given force per unit square and cross-sectional dimensions of the resilient members 44 and 45 are also selected so that the members 44 and 45, as well as the surfaces 42 and 43, will remain resilient in the direction perpendicular to the abutting surfaces 42 and 43 to thereby admit the probe 32 therebetween as shown in the drawing.

To this end the flanges 34 and 35 are provided with a plurality of longitudinally spaced threaded apertures 50 and the support members 46 and 47 are provided with a like number of longitudinally spaced apertures 51 which are elongated in a direction perpendicular to the abutting surfaces 42 and 43. Thus the amount of the abutting force per unit square between the surfaces 42 and 43 may be adjusted and balanced along the length of the conduit by fastening the support members 46 and 47 to the flanges 34 and 35 by means of bolts 52 when the proper registry between the apertures 50 and 51 has been established.

Referring to FIGS. 2, 3 and 4, it will be seen that the probe 32 comprises a hollow body 62 projecting into communication with the conduit 31 between the surfaces 42 and 43 from a manifold structure 63 which is mounted on the air pallet 13. The pipes 22 which conduct pressurized air to the air bearings 19 communicate with the manifold structure 63. Thus, pressurized air from the conduit 31 is supplied to the various air bearings 19 on the pallet 13 through the hollow body 62 of the probe and the manifold structure 63 through the pipes 22.

It will be understood that the cross-sectional area of the opening through the hollow body 62 of the probe 32 must be sufficient to enable the air flow therethrough to satisfy the needs of all of the air bearings 19 on the pallet 13. It will also be understood that the dimensions of the hollow body 62 perpendicular to the planar surfaces 42 and 43 must be small with respect to the dimensions of the elongated resilient members 44 and 45 perpendicular to the planar surfaces 42 and 43 but that the external dimensions of the hollow body 62 parallel to the plane of the opposed surfaces 42 and 43 may be as large as desired. Thus, as best shown in FIG. 4, the hollow body 62 of the probe 32 is elongated along the axis of elongation of the conduit 31 and the exterior surface thereof tapers from a dimension perpendicular to the abutting surfaces 42 and 43 which is a small portion of the dimensions of the resilient members 44 and 45 perpendicular to such surfaces to even smaller dimensions at each end thereof thus facilitating sliding movement of such hollow body 62 between the surfaces 42 and 43 in either direction along the axis of elongation of the conduit 31.

The walls of the hollow body 62 of the probe 32 must of course be capable of withstanding the maximum air pressure present in the conduit 31 in operation and the passageway 65 through the hollow body 62 will thus tend to be elongated along the axis of the conduit in order to provide the required cross-sectional area.

Although the embodiment shown in the drawings and described in detail hereinabove is specifically related to a system in which the fluid utilized is air, it will be understood that the teaching of this invention may be adapted to systems utilizing water or other fluids, as appropriate. it will also be understood that various modifications could be made in the structures specifically shown in the drawings and described hereinabove without departing from the teaching of this invention. For example, the conduit 31 need not be located beneath the pallet 13 but could instead be located above or to the side of the assembly line in a position to be engaged by an appropriately located probe 32 on the pallet 13. Similarly, one of the abutting surfaces 42 and 43 could be provided on a rigid portion of the conduit 31 with the other abutting surface provided on a single elongated member of resilient material. It would, of course,

be necessary to make an appropriate change in the exterior shape of the hollow body 62 of the probe 32 and the ability of such an arrangement to accommodate departures from a straight line in the path of the assembly line would be limited.

It is believed that those skilled in the art will make obvious modifications in the structure disclosed and described in this application without departing from the teaching thereof. Specifically it will be understood that various materials having the necessary physical characteristics to satisfy the teaching of this invention may be substituted for those specifically disclosed hereinabove. x

What is claimed is:

l. A system for supplying a continuous low volume flow of high pressure fluid to a mobile pallet or the like during movement thereof along a given path comprising a rigid fluid conducting probe means mounted on and projecting from said pallet or the like and an elongated sealed conduit connected to a source of pressurized fluid and extending along said given path, said conduit having wall means receiving said probe means therethrough and adapted to accommodate relative sliding movement of said probe means longitudinally with respect thereto while preventing the escape of pressurized fluid from said conduit other than through said fluid conducting probe means.

2. A system claimed in claim 1 wherein said wall means of said conduit comprises a pair of elongated parallel planar surfaces extending along the axis of elongation of said conduit and compressively abutting each other with given force per unit square, at least one of said pair of abutting surfaces being flexible in directions transverse thereof and being provided on an elongated member of resilient material, the cross-sectional dimensions of said elongated member of resilient material and said given force of abutment per unit square being sufficient to cause said elongated member of resilient material to be substantially rigid with respect to the maximum fluid pressure in said conduit while retaining resilience perpendicular to said pair of abutting surfaces.

3. A system as claimed in claim 2 wherein said probe means comprises a hollow body of material capable of withstanding the maximum fluid pressure in said conduit received between said pair of abutting surfaces of said wall means of said conduit and communicating with the interior of said conduit, said hollow body having an internal cross-sectional area sufficient to conduct the desired flow of fluid at pressures approaching said maximum fluid pressure in said conduit, the exterior dimension of said hollow body being elongated parallel to said abutting surfaces and tapering along the axis of elongation of said conduit from a given dimension perpendicular to said abutting surfaces which is a small portion of the dimension of said elongated member of resilient material perpendicular to said abutting surfaces to still smaller dimensions at each end thereof.

4. A system as claimed in claim 3 wherein both of said pair of elongated parallel planar surfaces are flexible in directions transverse thereof and each is provided on a different one of a pair of elongated members of resilient material, the cross-sectional dimensions of said elongated members of resilient material and said given force of abutment per unit square of said surfaces being sufficient to cause said elongated members of resilient material to be substantially rigid with respect to the maximum fluid pressure in said conduit while retaining resilience perpendicular to said pair of abutting surfaces.

5. A system as claimed in claim 2 wherein said pair of elongated parallel abutting surfaces are provided by material having a low coefficient of friction.

6. A system as claimed in claim 4 including a pair of thin elongated planar strips of Teflon each bonded to a different one of said pair of elongated members of resilient material to provide said flexible elongated parallel planar surfaces in abutment with each other.

7. A system as claimed in claim 2 wherein the crosssectional dimensions and the mounting of said elongated member of resilient material are selected so that the forces exerted on the surface of said member exposed to the interior of said conduit by the fluid pressure in said conduit has a substantial component perpendicular to said pair of parallel planar abutting surfaces.

8. A system as claimed in claim 2 wherein said wall means of said conduit includes means for adjusting said given force of abutment between said pair of parallel planar surfaces.

9. A system as claimed in claim 3 wherein said given dimension of said probe perpendicular to said pair of parallel planar abutting surfaces is less than one quarter of said dimension of said elongated member of resilient material perpendicular to said pair of parallel planar abutting surfaces.

embedded therein and projecting from the opposite narrow surface thereof, said rigid flange members being adapted to be mounted on said conduit to provide said means for adjusting said given force of abutment between said pair of parallel planar surfaces 

1. A system for supplying a continuous low volume flow of high pressure fluid to a mobile pallet or the like during movement thereof along a given path comprising a rigid fluid conducting probe means mounted on and projecting from said pallet or the like and an elongated sealed conduit connected to a source of pressurized fluid and extending along said given path, said conduit having wall means receiving said probe means therethrough and adapted to accommodate relative sliding movement of said probe means longitudinally with respect thereto while preventing the escape of pressurized fluid from said conduit other than through said fluid conducting probe means.
 2. A system as claimed in claim 1 wherein said wall means of said conduit comprises a pair of elongated parallel planar surfaces extending along the axis of elongation of said conduit and compressively abutting each other with given force per unit square, at least one of said pair of abutting surfaces being flexible in directions transverse thereof and being provided on an elongated member of resilient material, the cross-sectional dimensions of said elongated member of resilient material and said given force of abutment per unit square being sufficient to cause said elongated member of resilient material to be substantially rigid with respect to the maximum fluid pressure in said conduit while retaining resilience perpendicular to said pair of abutting surfaces.
 3. A system as claimed in claim 2 wherein said probe means comprises a hollow body of material capable of withstanding the maximum fluid pressure in said conduit received between said pair of abutting surfaces of said wall means of said conduit and communicating with the interior of said conduit, said hollow body having an internal cross-sectional area sufficient to conduct the desired flow of fluid at pressures approaching said maximum fluid pressure in said conduit, the exterior dimension of said hollow body being elongated parallel to said abutting surfaces and tapering along the axis of elongation of said conduit from a given dimension perpendicular to said abutting surfaces which is a small portion of the dimension of said elongated member of resilient material perpendicular to said abutting surfaces to still smaller dimensions at each end thereof.
 4. A system as claimed in claim 3 wherein both of said pair of elongated parallel planar surfaces aRe flexible in directions transverse thereof and each is provided on a different one of a pair of elongated members of resilient material, the cross-sectional dimensions of said elongated members of resilient material and said given force of abutment per unit square of said surfaces being sufficient to cause said elongated members of resilient material to be substantially rigid with respect to the maximum fluid pressure in said conduit while retaining resilience perpendicular to said pair of abutting surfaces.
 5. A system as claimed in claim 2 wherein said pair of elongated parallel abutting surfaces are provided by material having a low coefficient of friction.
 6. A system as claimed in claim 4 including a pair of thin elongated planar strips of Teflon each bonded to a different one of said pair of elongated members of resilient material to provide said flexible elongated parallel planar surfaces in abutment with each other.
 7. A system as claimed in claim 2 wherein the cross-sectional dimensions and the mounting of said elongated member of resilient material are selected so that the forces exerted on the surface of said member exposed to the interior of said conduit by the fluid pressure in said conduit has a substantial component perpendicular to said pair of parallel planar abutting surfaces.
 8. A system as claimed in claim 2 wherein said wall means of said conduit includes means for adjusting said given force of abutment between said pair of parallel planar surfaces.
 9. A system as claimed in claim 3 wherein said given dimension of said probe perpendicular to said pair of parallel planar abutting surfaces is less than one quarter of said dimension of said elongated member of resilient material perpendicular to said pair of parallel planar abutting surfaces.
 10. A system as claimed in claim 8 wherein each member of said pair of elongated members of resilient material is generally rectangular in cross-section with one of the narrow surfaces of each carrying a different one of the pair of parallel planar abutting surfaces, and each of said members includes a rigid flange member embedded therein and projecting from the opposite narrow surface thereof, said rigid flange members being adapted to be mounted on said conduit to provide said means for adjusting said given force of abutment between said pair of parallel planar surfaces. 